Cast-iron car wheel



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' JULE M. KELLER, OF ST. LOUIS, MISSOURI, .AFSSIGNOR T AMERICAN CAR ANDFOUND- BY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

No Drawing.

To all whom it may concern;

Be it known that I, JULE M. KELLER, residing at St. Louis, Missouri,and, being a citizen of the United States, have'invented a certain newand useful Improvements in Cast-Iron Car Wheels, of which the followingis a full, clear, and exact description, such as will enable othersskilled in the art to which it appertains to make and to use the same,though it is to be understood that the invention is not limited to theexact details of construction described, as it is obvious that variousmodifications. thereof within the scope of the claims will occur topersons skilled in the art. This invention relates -to articles of castiron having chilled wearing surfaces and particularly to cast iron carwheels having chilled treads and it is an object of this invention toprovide an improved cast iron car wheel or other article having achilled tread or wearing surface in which copper is mixed with the 3% to4% of combined carbon, iron and other elements which constitute thechilled portion of a cast iron car wheel or other article.

' The chilled treads of car wheels are subjected to the grinding actionof the brake shoes and to the heating which results from the friction ofthe tread against the brake shoes. This heating raises the temperatureof the tread above the temperature of the body of the wheel causingstresses to be set up in the wheel which result in cracks or checks inthe tread surface of the wheel. These cracks deepen as the result of thestresses of service and the repeated heating and cooling due to thebrake aplications until a portion of the wheel tread is loosened. anddrops out rendering the wheel unfit for further service. In accordancewith this invention, to the mixture used for casting the wheels, copperis. added until the percentage of copper is between .6% and 3.5%, ithaving been found by test that less than the smaller amount of copperhas no'effect and copper in excess of the larger amount is left in thecasting in the uncombined state. The copper may be added tothe molteniron in the pouring ladle just prior to pouring the contents of theladle into the mold. There is thus formed a mixture with the copperdistributcasr-ino'lv can WHEEL.

Application filed August 14, 19251 Serial No. 50,313.

ed throughout so that when the wheel is cast the copper I is distributedthroughout the casting and is present in the chilled portion of thewheel at the tread along with the combined carbon, silicon, manganese,phosphorous, sulphur and iron which go tomake up a cast wheel.

Tests by the sclerescope and by the Brinell test indicate that thepresence of the copper in the chilled portion of the wheel does notreduce the hardness below that of the chilled portion of a casting madewithout the copper and the presence of the copper prevents the checkingor cracking of the wheel tread caused by the heat from the applicationof. the brake shoes and the resulting dropping out of portions of thetread as in the present cast iron wheels. The results 'of service con- 7firm the results of thermal tests of the wheel treads made by subjectingthe wheel treads tothe heat of molten iron poured into a mold formedabout the tread of the wheel; In all thermal tests the threads of wheelscontaining copper show few, if any, cracks or checks in the chilledWeartread while the chilled wear treads of the wheels not containingcopper are cracked and checked.

Applicant is unaware of the exactmetallurgical effect of the addedcopper but tests have shown that the chilled wear treads of cast ironwheels made in accordance with this invention are of Substantially thesame hardness as the chilled wear treads of cast 35 iron wheels made inthe usual manner and aresubstantially free from the cracking or checkingof the chilled wear tread in service to which cast iron wheels areordinarily subject.

. a While this invention has been described "in connection with castiron wheels, it is to be understood that it is equally applicable to anycast iron article having a chilled wear surface that is subjected toalternate heatings and coolings in service due to friction thereon or toother conditions of service.

What is claimed is: I

1. As a new article of manufacture, a chilled cast iron having from 3%to 4% 1100 of combined carbon and from- .6% to 3.5% of copper.

2. An article of cast iron having a chilled portion containing from 3%to 4% of combined carbon and from .6% to 3.5% of cop- 4. A cast iron carwheel having a chilled per. tread portion containing from 3% to 4% 3'. Acast iron article having a chilled porof combined carbon and from .6% to3.5% 10 tion forming in wear surface, saiq chilled of copper. 5 portioncontaining from 3% to 4% of com- In Witness whereof I have hereunto setbined carbon and from .6% to 3.5% of copmy hand.

per. f JULE M. KELLER.

